CN-0359 testing

Hi!

After reading the CN-0359 application note, I am purchasing at Digikey online shop and testing the EVAL-CN-0359 board.

There were a few problems in the process of testing.

The questions are in the attachment file.

Please give me good advice.

Thank you.

Best regards.

CN-0359 test and Q_.zip

Is it caused by contact potential???

  • Hi Mark,

    Now I will understand your will.
    "The error caused by the 1M Ohm resistor connected to J5P3 is known and can be compensated in software."
    I will summarize it like this.

    Thank you in the meantime.

    Kwon

  • 0
    •  Analog Employees 
    on Jan 22, 2020 4:34 AM in reply to ksw280

    We'd be interested in your results, it appears there's some subtle issues with certain probes. On that note, can you provide the part number for the probe you're using, or is it your own proprietary design?

    -Mark

  • It is our own proprietary design, looks like bull's eye. Please refer to the attached photo for the shape.

    Kwon

  • 0
    •  Analog Employees 
    on Jan 23, 2020 1:13 AM in reply to ksw280

    Understood - just speculating, but if your sense electrodes are very small, then you may indeed need to take special precautions and use picoamp bias current op-amps on both.

    -Mark